[RFC] arm: add __initbss section attribute

[Arnd Bergmann]

On Tuesday 13 October 2015 15:33:10 yalin wang wrote:
> 
> > On Oct 13, 2015, at 04:04, Sam Ravnborg <sam at ravnborg.org> wrote:
> > 
> >> --- a/include/asm-generic/vmlinux.lds.h
> >> +++ b/include/asm-generic/vmlinux.lds.h
> >> 
> >> -#define BSS_SECTION(sbss_align, bss_align, stop_align)			\
> >> +#define BSS_SECTION(sbss_align, bss_align, initbss_align, stop_align)			\
> > 
> > A few comments:
> > 
> > 1) - please align the backslash at the end of the
> >     line with the backslash above it.
> > 2) - you need to fix all the remaining users of BSS_SECTION.
> > 3) - do we really need the flexibility to specify an alignment (stop_align)?
> >        If not - drop the extra argument.
> > 
> > 	Sam
> i change lots of __initdata to __initbss to test it on ARM arch,
> 

Ok, I found my mistake in the script I used to calculate the savings,
here is the correct output showing all uninitialized variables in
multi_v7_defconfig:

4	done.44688
1024	boot_command_line
1024	tmp_cmdline.44689
4	late_time_init
4	root_mount_data
4	root_fs_names
4	rd_doload
4	root_delay
64	saved_root_name
4	root_device_name
4	message
4	byte_count
4	victim
4	collected
8	this_header
4	state
4	collect
4	remains
4	next_state
8	header_buf
8	next_header
4	do_retain_initrd
4	name_len
4	body_len
4	gid
4	uid
4	mtime
4	wfd
4	vcollected
4	ino
4	mode
4	nlink
4	major
4	minor
4	rdev
4	symlink_buf
4	name_buf
64	msg_buf.29770
128	head
4	machine_desc
4	usermem.34390
4	__atags_pointer
1024	cmd_line
1024	default_command_line
1536	atags_copy
4	dma_mmu_remap_num
64	dma_mmu_remap
4	phys_initrd_start
4024	phys_initrd_size
4096	bm_pte
4	ecc_mask
4	initial_pmd_value
4	arm_lowmem_limit
24	s5p_mfc_mem
28	tx_pad_name
4	use_gptimer_clksrc
4	omap_table_init
4	mpurate
4	am35xx_aes_hwmod_ocp_ifs
4	am35xx_sham_hwmod_ocp_ifs
4	dra72x_hwmod_ocp_ifs
4	rx51_vibra_data
4	num_special_pds
128	special_pds
4	main_extable_sort_needed
4	new_log_buf_len
24	opts.36513
512	smap.22469
512	dmap.22470
64	group_map.22521
64	group_cnt.22522
4	pcpu_chosen_fc
4	vmlist
4	vm_init_off.26867
4	reset_managed_pages_done
116	boot_kmem_cache_node.32827
116	boot_kmem_cache.32826
4	dhash_entries
4	ihash_entries
4	mhash_entries
4	mphash_entries
256	nfs_root_parms
1028	nfs_export_path
1028	nfs_root_device
4	gic_cnt
4	threshold_index
4096	ata_force_param_buf
4	mtd_devs
2432	mtd_dev_param
8	m68k_probes
8	isa_probes
4	arch_timers_present
4	dt_root_size_cells
4	dt_root_addr_cells
4	imx_keep_uart_clocks
4	imx_uart_clocks
4	mt8173_top_clk_data
4	mt8173_pll_clk_data
4	cpg_mode
4	cpg_mode_rates
4	cpg_mode_divs
4	cpg_mode
4	cpg_mode
4	thash_entries
4	uhash_entries
4	ic_got_reply
4	ic_first_dev
4	ic_dev
16	user_dev_name
4	ic_dhcp_msgtype
4	ic_host_name_set
4	ic_dev_mtu
4	ic_set_manually
4	ic_enable
256	vendor_class_identifier
4	ic_proto_have_if
4	dma_reserve
4	nr_kernel_pages
4	nr_all_pages
196	__clk_of_table_sentinel
200	__rmem_of_table_sentinel
196	__clksrc_of_table_sentinel
200	__iommu_of_table_sentinel
8	__cpu_method_of_table_sentinel
8	__cpuidle_method_of_table_sentinel
196	irqchip_of_match_end
32	__earlycon_table_sentinel
200	__earlycon_of_table_sentinel
6	__irf_end


26398 total